Influence of the Mushy Zone Constant on the Numerical Simulation of the Melting and Solidification Process of Phase Change Materials

摘要

The present paper deals with the numerical modelling and simulation of latent heat thermal energy storage systems. The results of a numerical analysis on the influence of the so called mushy zone constant C on the melting and solidification process of phase change material (PCM) will be discussed. The mushy zone constant C is part of the Carman-Kozeny equation which is used to introduce a damping term in the momentum equation to model the fluid flow in the mushy zone as fluid flow through a porous medium. The analysis presented shows a comparison of the simulation results obtained by a variation of the mushy zone constant from C = 10~5 to C = 10~8. A comparison of the chronological sequence of the liquid fraction of sodium nitrate (NaNO3) for a variation in the mushy parameter shows that the overall time for complete melting and solidification of the PCM increases with higher mushy zone constant C. Moreover the mushy zone constant has also an essential influence on the morphology of the melting front as the inclination of the melting front approaches to the vertical direction with increasing mushy zone constant.